Dr. Abeer S. Amin
Faculty of Science, Suez Canal University, Ismailia, Egypt
Toxinogenic algae are found in the divisions Chrysophyta, Pyrrhophyta, and Cyanophyta. The latter are ancient phototrophic prokaryotes naturally occurring in most aquatic ecosystems. The phytoplankton community particularly in eutrophic systems cause most of the problems in freshwater habitats. Cyanobacteria are major producers of odor compounds such as geosmin and methylisoborneol. They also produce other organic compounds that may react with chemical disinfectants to produce toxins that may be ingested with drinking water. The majority of the known seafood toxin syndromes are associated with bivalves that can accumulate a variety of toxins produced by dinoflagellates (Pyrrhophyta) and diatoms (Chrysophyta). These include the paralytic shellfish poisons (PSP), diarrhetic shellfish poisons (DSP), neurologic shellfish poisons (NSP), and Domoic acid, responsible for amnesic shellfish poisons (ASP). Toxic cyanobacterial (blue-green algae) water blooms are found worldwide in eutrophic lakes, ponds, drinking water reservoirs and coastal waters. They can produce neurotoxic, hepatotoxic and dermatotoxic compounds that threat animal and human water supplies. Some of the toxic species of algae in Egypt are Anabaena circinalis, Anabaena flos-aquae, Anabaena variabilis, Aphanizomenon flos-aquae, Oscillatoria brevis, Oscillatoria limnetica, Oscillatoria agahrdhii, Microcysistis aeruginosa, Cylindrospermposis raciborskii, Nodularia spumigena, Nitzschia pungens, Pseudonitzschia delictissima, and Alexandrium tamarense.